[testing] How to create large PDF files (10MB, 50MB, 100MB, 200MB, 500MB, 1GB, etc.) for testing purposes?

according to http://www.maketecheasier.com/combine-multiple-pdf-files-with-pdftk/ the command should be

pdftk file1.pdf file2.pdf file3.pdf cat output newfile.pdf

note that you should download windows version of pdftk